outlook anywhere internal hostname

Hi,

We have an exchange 2010 server. We have renewed our certificates. Because internal servernames cant be included in the certificates anymore, we have changed the internal hostnames for owa, ecp, oab etc etc. But we cant change the internal hostname for outlook anywhere.

Now the clients keep getting certificate mismatch error after starting outlook.

I was trying to change the internal hostname with the following command.

Set-OutlookAnywhere -Identity "HostName\Rpc (Default Web Site)" -InternalHostname mail.mydomain.com -InternalClientsRequireSsl $true

A positional parameter cannot be found that accepts argument '-InternalHostname'.
   + CategoryInfo          : InvalidArgument: (:) [Set-OutlookAnywhere], ParameterBindingException
   + FullyQualifiedErrorId : PositionalParameterNotFound,Set-OutlookAnywhere

Any help is apreciated.

Regards